Window motor or Regulator?

Over the last few months both of the windows on my 99 silverado have become worse and worse. Some days they will work fine and most other days they are either very slow or do not work at all. i have tried greasing up the tracks but is still doing the same thing and have gotten worse over time (especially cold temperatures)...I am trying to find out whether i just replace the motor or both motor and regulator kit.

If it were me I would just replace both. From experience on the used car lot here, almost every one we have replaced a motor in we have had to put in a new regulator as well. If we didn't, we ended up putting one in within 3 or 4 months anyway. :grrrrrr:
Just my two cents..but I would just save myself the time and trouble and do them both at once.
Good luck to you.

i agree with Loggerhead Mike & shooter. replace both the regulator and the motor. 2 years ago, my drivers side window just stopped working. so i just replaced the motor since the regulator was still ok. then 2 months after i had to replace the regulator due to the cable snapping. & plus prior to it snapping, it was not going up and down slower than usual.